Coated material



Jan. 5,r 1937. c. F. SCHMIDT, JR.. Ax-:T AL 2,057,066

COATED MATERIAL Filed June 19, 195s r M55 waff WML/MM' Patented Jan.' 5e, 1937,A

PATENTl OFFICE 2,067,066 4COATED MATERIAL Clifton F. Schmidt, Jr., and George L. Ball,

Pittsburgh, Pa.

lApplication June 19, 1933, Serial No. 676,540

2 Claims. i (Cl. B15-37) This invention relates to a fibrous or pulpous flexible and compressible material, so coated as to preserve its exibility and compressibility, while supplying the material with a sealing coating, which' is tough and flexible, and which is insoluble and chemically neutral.

A further object of the invention is to provide a material coated in this manner which may be economically manufactured, so that together with its other characteristics it is eminently suited to use as a liner for bottle caps and other closures applied to containers for foods, beverages, cosmetics, and various chemicals and other materials.

We have found that if a sealing coat having a resoleate base be applied directly to a porous absorbent material, such as pulp or fiber board, the

coating ma/terial so saturates the board as to a closure to a container.

cause waste of the coating material and to impair the fiexibility and compressibility of the board.' Such board is therefore unsuitable as a liner for bottle caps and similanclosures, in that it does not conform to the edge of the neck or other opening of the container, by compression,

to provide a tight seal in the closure. We have further discovered that a compressible absorbent material coated with a colloidal material alone is not wholly suitable for such purposes. Such material is thermoplastic, thus tending to cement It isof such nature that it may be aifectedby certain foods, beverages, cosmetics, and so forth, which are usually` put up in containers to which a lined closure may be applied.

We have discovered that we may render a compressible absorbent material, such as pulp or fiberboard generally suitable for use in making liners for bottle caps, and for similar uses, by first applying to a surface of the material a stop coat or coats of a suitable colloidal coating material; and by applying to the underlying coat an overlying coating of a suitable resoleate base coating material. This outer coating gives the material a flexible, elastic and wholly coherent outer skin or covering, which is in itself neutral, and which is highly resistant to acids, fumes, salts, and p'roducts of fermentation.

For application it -is necessary that the colloidal material be prepared withv suitable evaporative solvents,.and that the coating compositiony 'comprising it contains a sufficient percentage' of the solidingredient to ldeposit a substantial film-on a surface to which the coating composition is applied.

VWe have discovered that an inexpensive and particularly desirable colloidal coating fluid may be made by suitably dissolving photographic film, which when used and discarded is a waste material. The photographic film used by us contains in its composition nitro-'cellulose and various plasticizers. By the term photographic film,. 5 as used throughout the specification and claims, we therefore intend to designate nitro-cellulose film, which is the photographic film in most common use, and not cellulose acetate film.

The difficulty which has been experienced in the `1o application of a solution of photographic film to a surface is due tothe fictitious viscosity or apparent body of' the film material in solution. I'hat is, when a coating material comprising photographic film, dissolved in the solvents previous- 15 ly used, is applied to a surface, such a small quantityl of the solid ingredient has been dissolved l initially, and deposited on the surface, that an. adequate film is not formed. In orderthat an adequate quantity of material be deposited on a surface to form a substantial film, it is necessary that there be a sufficient quantity of the filmforming solid in any given volumeof solvent.

We have discovered that we can obtain a flowable coating material of honest body by produc-- ing a base solution of photographic film in acetone as the sole solvent for the photographic film. We have found that if acetone, without substantial admixture of other solvents, be used, we 'can diS- solve more than two pounds of scrap photographic film in each gallon of acetone. In this solvent, used alone, the scrap photographic film loses its i tendency toward fictitious viscosity, and an adeter of body is of prime importance in securing a deep, dense, and uniform film, we vprefer to use our base solution, either alone or mixed with other film-forming materials, without the addition of any substantial quantity of thinning 50 fluds.`

In order that a coating material of great elasticity may be produced, utilizing our base solution, we may mix it with a processed oil, which has, in admixture, the quality of producing films 55 as news board or the like, which is to be cut into parts of pine oil to 1 part of butyl lactate'.

of great elasticity. Such oil may be one of the highly rened, highly oxidized, aerated, linseed oils, which are in general use, and which fall within the loose trade designation of blown oils. A preferred oil for admixture, however, is the processed linseed oil sold by Archer-Daniels- Midlandl Company `under the name A.D. M. 100 oil.

The oil known by the trade name of A. D. M. 100 oil is a drying oil, preferably linseed oil, which has been oxidized, at temperatures relatively so low as to prevent undue polymerization, and which has undergone under these low ternperature conditions oxidation suiiicient lto render the oil soluble in ethyl alcohol. The oil as used is in the form of a solution in about 15% of ethyl alcohol.

For the reasons explained in our co-pending application, Serial No. 676,527, filed June 19, 1933, the blown oil of common production may be commingled with the base solution in a quantity by weight of from one-fifth the weight of the photographic film content up to the weight of the photographic film content. The A. D. M. 1'00 oil we may mix with the base solution in a weight of from equality with the weight of the photographic lm content up to four times the Weight of the photographic film content. Both the highly oxidized highly refined blown" oil of common production, and the specialized processed linseed oil known as A. D. M. 100 oil are film-forming materials, and the latter has the quality of entering wholly into film formation to provide an extraordinary toughening and plasticizing effect in the lm as a whole.

For our present purpose, that is, the formation of a stop coat on absorbent material, such liners for closure caps, or into gaskets and the like, we prefer touse the A. D.'M. 100 oil in relatively great quantity with respect to the photographic'film content of the base solution. We have found a tWo-to-one mixture of A. D. M. 100 oil with the base solution thoroughly satisfactory for use as 'a stop coat in the coating of pine oil, butyl lactate, or a mixture of these Y fluids.

A preferred regulatory fluid is the mixture of pine oil and butyl lactate, in the proportion of 2 This we desirably addto the base solution, or to the mixture of base solution and processed oil,' in a quantity of from 10 to 14 ounces of regulatory fluid to each gallon of base solution, or 5 to 10 ounces of regulatory fluid to a mixture of base solution and processed oil. l

As a substitute for the butyl lactate, as a regulatory fluid, we may use hexalin, methyl hexalin, or butyl cellosolve which is the monobutyl ether of ethylene glycol. As a .substitute for pine oil, we mayluse dipentene, a fluid having a body midway between that of pine oil and that of wood turpentine.

'Ihe regulatory fiuid serves as a general cor-- rective, present in the coating material, for atmospheric conditions which might otherwise be unfavorable, by lowering the dew point of the coating material, and preventing blushing in the film formed from the coating material.

' 'I'he coating material may be applied to a surface which is to be covered by wiping, brushing, spraying, or by rolling the material on the surface. It also may be used as a dip coating. Our preferred manner of application is to place an excess of the coating material on a surface to be coated, and to spread it evenly thereon, removing surplus material, by use of a, doctor knife, or other suitable scraper. This mode of application is particularly desirable for applying the coating material to a pulp or fibre board, such as news board, for the reason that the' nap of the base material is smoothed down as the coating material is applied.

After application, the coating is subjected de- -sirably to forced evaporation, at such moderate temperature, not in excess of 300 Fahrenheit', as will not tend to injure the film formed by evaporation, or the material on which the dcoating material has been spread.

It is an advantage of our coating material that it anchors firmly tothe surface of an absorbent material, such as a pulpous or fibrous board, or to the surface of a closely woven fabric suchas canvas, without penetrating the body of the material coated to any appreciable extent.

In the accompanying drawing, Figure I illustrates on a greatly enlarged'scale a section of pulp or fiber board with our stop coat spread thereon; Figure II is a similar view, but showing the material with a resistant coat also applied over the colloidal stop coat and forming a wholly coherent film thereon; Figure III is a crosssectional view through a bottle cap and liner on a greatly enlarged scale, the liner being composed of our specially coated board; Figure IV is a cross-sectional view through the same bottle cap, showing the compression of the liner attendant upon use of the cap as a closure for a bottle; and Figure V is a cross-sectional view through a similar bottle cap, illustrating the use of a lining board which has received a colloidal coating on both of its surfaces.

Referringto Figure I of the drawing, the intermediate product as shown therein, and as described above, comprises the pulp or fiberboard proper, designated by reference numeral I. Reference numeral 2 designates the colloidal stop coat remaining after evaporation of the solvents. It will be noted that this stop coat 2 does not penetrate deeply into the board I, although it is anchored to it.

'Ihe board, with the stop coat 2 dried thereon, is then in condition for a resistant, or contact, coat designated by reference numeral 3 in Figure II, and succeeding figures of the drawing. This outer contact coat may be any suitable coating material providing when dry an elastic film which is wholly continuous, which is of itself neutral, and which is resistant to the action of acids, salts, alkaline materials, andfl the products of fermentation. While various coating materials, such as waxes and various synthetic resin base coatings, fulfill these requirements in greater or lesser degree, we have found by experiment that a peculiarly satisfactory outer coating is obtained by reducing a resin of the modified ester gum and oil type to a varnishlike consistency with suitable quantities of petroleum, pine oil and coal tar distillate. 'I'his coating we apply in any suitable and or otherwise detract from its flexibility andA compressibility. It will be noted further, from this ligure of the drawing, that the outer, or contact coating serves to fill any minute apertures which may be present in the stop coat. Such minute apertures are of very rare occurrence with the preferred coating material hereinbefore disclosed, for the reason that it is formed speciiically to provide a dense coating, of uniform depth, and

. without pin holes or other weakness.

Figure-III of the drawing shows the use of our prepared board as a liner in a suitable crimped metallic shell d, the shell and liner constituting a sealing and impervious bottle cap.

Figure IV of the drawing illustrates the manner in which both the board itself and the elastic coating thereon seals against the mouth 5 of a bottle or the like. `It is to be observed in this is wholly impervious and which is not attacked by the contents ofthe vessel to which the closure member has been applied. v

In Figure V of the drawing, a colloidal coating has been applied to both faces of the board. In

this instance the coating t, which lies against the inner surface of the bottle cap t, serves to cement the liner in the shell if it be heated, or provided with a drop of solvent, and pressed firmly into the shell.

We have referred above to the fact that we prefer a iinishing coat of special coating material produced by reducing a resin of themodied ester gum and oil type to a varnish-like consistency. Coating materials of this type may be made up of various initial ingredients and according to various methods of manufacture; but all may properly be described as rcsoleate base materials, involving as they do the heat treatment of a modiiied ester gum with a suitable oil. We may, however, give a typical example of the procedure in making up the resolcate base for such coating material.

The starting material is a modified ester gum, and we have found satisfactory the modified gum known'as Lewisol No. 2, and widely sold under that name by John T. Lewis, of Providence, Rhode Island. While the exact composition of this resin is a trade secret, a resin may be made having qualities suiciently like that of Lewisol No. 2 to be satisfactory for our purpose by esterizing rosin, and fusing the esterized rosin with a fatty acid, such as the fatty acid of linseed oil or China-wood oil. y

'I'he modied ester gum may then be worked up into a resoleate base by the following procedure. Assuming that Lewisol No. 2 is the modiiied ester -gum used, it is heated to 525 F. with a portion of China-wood oil. When this .temperature .is reached, it is'checked with a part of the total lquantity of China-wood oil, and when the temperature of 525 F. is again reached, it is checked with the balance of the China-wood oil.

The and China-wood -oil is again brought to 525 F., and an alkali-rened linseed oil, cooked to give heavy body, is added. The batch is heid at a temperature of 525 F. for a period of about one hour, to give body, is cooled, and reduced. The quantity of China-wood oil and linseed oil may be varied in accordance with the desired elasticity vof the resulting products, but the total quantity of oil should desirably lie within the range of 20 to 40 gallons for each 100 pounds of resin. The resulting product is a viscous resoleate material.

Instead of Lewisol No. 2, as the starting resin,

we may use Amberol No. 801, widely sold under that designation by Resinous Products and Chemical Company, Inc., of Philadelphia, Pennsylvania; or we may use Beckacite No./1112, widely sold under that designation by Beck, Koller and Company, Inc., of Detroit, Michigan.

This outer, or contact, coat as so formed is clear, transparent, is free from after-yellowing, and provides a good vehicle for pigment, if a colored product is desired. The coated material, after application of the contact coat, should be heat treated at a` temperature not in excess of 300 F., in order that it maynot injure inammable material, to which the two diverse coatingshave been applied. The heat treatment should be conducted for a substantial period,` as from thirty to sixty minutes, in order to convert the outer coating material to insolubility and complete neutrality.

As so treated, the coating material is odorless,

tasteless, sterile, is highly resistant to the action `of acids and alkalis, and presents unusual resist- Awater, food juices, and substantially all liquids which occur with food products, toilet preparations, or'th'e like, which4 are sold in capped containers. Thesequalities render the use of an inexpensive, compressible material4 such as news board, when coated as described, peculiarly suitable or use inmaking lines for bottle caps, jar covers, and the like. In addition, the elasticity of both the stop coat and the outer, or contact, coat serves to produce a close, impervious seal with the edge of a bottle neck, jar, or the like.

One result of the forced evaporation to which the stop coat is subjected, and the heat treatmen-t to which the contact coat is subjected, is-

to so dry the news board, or other similar material, that it becomes too dry to be readily punched orstamped into shapedpieces, such as the circular pieces used as liners for closure caps. For this reason, the material, after heat treatment, is desirably treated in a humidier. As the sterility of the material would be impaired by such moistening, it would notbe then so suitable for use as lining material in the closure caps of food and beverage containers. To avoid loss of sterility, when the coated material is to be used for such purpose, we pse in the humidifier a dilute germicidal solution. We have ound It thus differs widely from bottle cap liners which comprise a base of cork composition, or cork sub- -treated, adhesively attached thereto.

Because our material, considered as a closure cap liner, is a single piece article. it may be manufactured with an economy in manufacturing steps or operations. 'Ihat is the news board, or its substantial equivalent, may be coated in continuous lengths, and made into single piece closure cap liners merely by a machine punching, without any finishing treatment.

It should be understood that where the word coat is used throughout the specification and claims, it should be held to describe a coating formed by more than one application of coating material, as well as a coating formed by one application alone.

This is a continuation in part of our previously led application, Serial No. 624,044, led July 22, 1932, for an improvement in Coated material.

We claim as our invention:

1. A .single piece liner for use in container cap closures composite of an absorbent and compressible fibrous or pulpous board base and a double coating of diverse layers covering one face of said absorbent and compressible base; the said coating comprising an elastic primarily clear and non-penetrating stop coat of nitrocellulose llm together with an oxidized alcohol-soluble and alcohol-containing linseed oil of but slight polymerization forming a stop coat anchored to the absorbent base, and an elastic impermeable contact coat 'of coating material comprising a modified ester gum and oil resin heat cured to a condition of relative insolubility overlying the said stop coat and separated from the absorbent and compressible base thereby.

2. A single piece liner for use in container cap closures composite of an absorbent and compressible brous board base and a double coating of diverse layers covering one face of said absorbent and compressible base, the said coating comprising an elastic primarily clear and non-penetrating stop coat of nitrocellulose photographic film together with an oxidized alcoholsoluble and alcohol-containing linseed oil of but slight polymerization forming a stop coat anchored to the absorbent base, and an elastic impermeable contact coat of coating material comprising a modified ester gum and oil resin heat cured to a condition of relative insolubility overlying the said stop coat and separated from the absorbent and compressible base thereby.

CLIFTON F. SCHMIDT, JR. GEORGE IL. BALL. 

